In the related art, as a valve configured to control a flow of a fluid in a fluid path formed at a joining surface between a first substrate and a second substrate constituting a stacked substrate, a valve, which includes a three-layer structure body in which a resin sheet is sandwiched by interfaces of the first substrate and the second substrate, is known. (Non-Patent Document 1).
FIG. 1 shows a cross section of a valve having a conventional three-layer structure body. A resin sheet 111 is stacked on an entire upper surface of a first substrate 110, and a second substrate 112 is further stacked thereon. A groove is engraved on a lower surface of the second substrate 112, the resin sheet 111 is joined to the lower surface of the second substrate 112 to cover the groove, and a fluid path 114 is formed. An arrow facing right in the drawing indicates that a fluid path extends in a right direction in the paper and a fluid flows in the right direction in the paper. Also, a through hole 113 is provided in the first substrate 110. Here, when a pressure is applied to the resin sheet 111 from an inside of the through hole by feeding air, the resin sheet 111 swells upward, the fluid path is blocked, and thus a flow of the fluid is disturbed (refer to FIG. 2). Also, when an air pressure is released, a resin sheet is returned to an original flat shape by its own elasticity. The resin sheet 111 serves as a diaphragm member of the valve through such pressure control.